Copper cobalt alloy



' PateniedfAug. 6 1929.

UNITED STATES PATENT, OFFICE.

MICHAEL G. CURSOR", OF JACKSON HEIGHTS, NEW YORK, ASSIGNOR T ELECTRO METALLURGICAL COMPANY, A CORLPORA'I'ION OF WEST VIRGINIA.

'corrnn COBALT ALLDY.

1N0 Drawing.

The invention is a group of alloys containmg copper and cobalt.- I have discovered that copper alloys containing 2% or more of cobalt are remark- C. At somewhat lower temperatures the alloys resist annealing indefinitely. In addition to these unusual properties the alloys of the invention possess the resistance to corrosion and other known characteristics of the copper alloys, and this combination of properties renders them valuable for many purposes. Y

To prepare an alloy of this class for use it is first heated to a temperature between 850 C. and its melting point, and held at i such temperature until the cobalt is in solid solution. The alloy is then quenched from this temperatureend thereby hardened. lhe hardness andstrength can be increased by cold work. The cold-Worked alloy retains a large proportion of its stren th and hardness when heated to moderate y high temperatures although its ductility is increased by such heating. Thus at temperatures as high as 700 (l, a binary alloy con- Application filed April 13, 1926. Serial No. 101,812.

taining 3% of cobalt may show a Brinell hardness of 90 and a tensile strength of over 55,000 with the ductility indicated by an elongation of 25%. p

The invention is not restricted to binary alloys as cobalt has a similar eiiect when added to any of the alpha alloys of copper, for example its alpha alloys with zinc, alumi num, tin, or manganese. The cobalt contentof the alloys may of course be increased as desired but because of the present high price of cobalt it is preferred to keep it in the vicinity of 2 to 5%.

I claim:

- 1. The method of treating copper to improve the physical strength thereof which consists in alloyin it with 2% to 5% of cobalt, heating the alloy to a temperature above C. and quenching from that temperature.

pounds per square inch, combined 2. The method of making non-annealable I corrosion resisting articles which comprises forming an article from an alloy consisting predominantly of copper, and containing not less than 2% of cobalt, and no more cobalt than can be caused to go into solid solution at 850 (1., and quenching the article from a temperature above 850 C. In testimony whereof, I alfix my-signatureL MICHAEL e. GORSON. I 

